Calculating the Fertilizer Value ... - University of Georgia

Calculating the Fertilizer Value of Broiler LitterDavid E. Kissel, Mark Risse, Leticia Sonon and Glen Harris

Given below is a procedure to calculate the value of broiler litter based on prevailing retail selling prices of commercial2 5fertilizers containing nitrogen (N), phosphorus (P) labeled as %P O (the oxide expression used in the fertilizer industry)

2and potassium (K) labeled as %K O. The calculation is based on an average broiler litter composition from the UGA Soil,2 5 2Plant, and Water Laboratory of 3.1 percent N, 3.1 percent P O , and 2.8 percent K O. Because different fertilizer materials

contain different concentrations of N, P and K, the first step will be to calculate the cost per pound of each of the primary2 5 2 nutrients expressed as the N, P O and K O contained in them. Steps in this assessment are as follows:

STEP 1. Determine the cost per pound of available nutrients. Calculate the cost per pound of nutrients as follows:

Cost per pound = retail price per ton divided by the pounds of nutrient per ton. Nutrients per ton are given below for N, P and K fertilizers. For example:

Urea contains 920 pounds of N per ton. If the cost is $600 per ton, then the cost per pound is $600/920 = $0.65 per pound of N. Another example: If Muriate of Potash costs $960/ton, then the cost per pound is $960/1,200 = $0.80 per

2pound of K O.

Nitrogen Fertilizers

Name % N lbs. N/ton

Ammonium Nitrate (34-0-0) 34 680

Ammonium Sulfate (21-0-0) 21 420

Urea (46-0-0) 46 920

UAN Solution (32-0-0) 32 640

Phosphorus Fertilizers

2 5 2 5Name % P O lbs. P O /ton

Triple Superphosphate (0-46-0) 46 920

Monoammonium Phosphate (11-52-0) 52 1,040

Diammonium Phosphate (18-46-0) 46 920

Ammonium Polyphosphate (10-34-0) 34 680

Potash Fertilizers

22Name % K O lbs. K O /ton

Muriate of Potash (0-0-60) 60 1,200

Sulfate of Potash (0-0-50) 50 1,000

Sulfate of Potash Magnesia (0-0-20) 22 440

2 5 2STEP 2. Determine the equivalent N, P O and K O values per ton of litter.2 5 2Using the calculated price for N, P O and K O in step one, go to the step two table below and find the equivalent

2 5 2fertilizer value per ton of litter that contains 3.1 percent N, 3.1 percent P O and 2.8 percent K O.

2 5 2Nitrogen (N) Phosphate (P O ) Potash (K O)

2 5 2$/lb. N $/ton PL $/lb. P O $/ton PL $/lb. K O $/ton PL*

0.4 12.40 0.4 22.32 0.3 16.80

0.5 15.50 0.5 27.90 0.4 22.40

0.6 18.60 0.6 33.48 0.5 28.00

0.7 21.70 0.7 39.06 0.6 33.60

0.8 24.80 0.8 44.64 0.7 39.20

0.9 27.90 0.9 50.22 0.8 44.80

1.0 31.00 1.0 55.80 0.9 50.40

* Assumes N is 50% available inpoultry litter (PL) not incorporated.If incorporated into soil, multiply by1.3.

2 5* Assumes P O in PL is 90%available.

2* Assumes K O in PL is 100%available.

STEP 3. Add the total fertilizer value for N, P and K in dollars per ton of litter.2 5 2As an example, for N, P O and K O (valued at $0.60, $0.50 and $0.30 per pound, respectively), the litter value based

only on the N, P and K values would be $18.60 + $27.90 + $16.80 = $63.30 per ton.

If fewer than three of the nutrients are needed for a particular crop and field, just add the value of the nutrients that areneeded. For pastures that have received litter for many years, soil test P and K values may be high. If so, P and Kfertilizers are not needed. In such a case, applying the litter to this pasture may be wasteful if only N is needed. In theexample above, the P and K value was equal to $44.70 per ton, more than enough value to purchase an amount of Nfertilizer equal to the N contained in one ton of the litter (valued at $18.60). In this case, the poultry farmer could then sellthe litter to other farmers who need all three nutrients for crop production, and use the money from the sale to purchase Nfertilizer for the pasture.

Special notes: Although there is additional value from micronutrients, it is difficult to determine because micronutrientsare often in adequate amounts in agricultural soils. In addition, there is evidence that less agricultural lime is needed whenpoultry litter is used for crop production (Endale et al., USDA-ARS Southern Piedmont Experiment Station). We estimatethis liming value at $3 per ton. The organic matter in litter also improves the soil.

The above calculations are based on average values of nutrients in broiler litter at the UGA laboratory. A web-basedcalculator is located at http://aesl.ces.uga.edu/fertcalc.htm for analysis values that differ from those given above. Broilerlitter should be tested to accurately determine its nutrient content (contact your county agent for information about littertesting). Broiler litter is not as convenient to use as commercial fertilizer and includes additional costs for hauling andspreading that depend on local conditions.

Circular 933 Reviewed October 2015

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